Method and apparatus for applying printing sheets to their cylinders



Dec. 8, 1925.

M. OWEN METHOD AND APPARATUS FOR APPLYING PRINTING SHEETS TO THEIR CYLINDERS Filed Feb. 12.

Patented Dec. t3, i925.

MALCOLM Git EN, OF LONDQN, ENGLAND.

METHOD AND APPARATUS FOR APPIIIZING FEIlTTEI'IG all Application filed February 12, 1924:. Serial No. 692,499.

To all iii/10m it may concern:

Be it known that l, lafiaioonrr OWEN, a subject of the King of Great Britain, residing at 109 Farringdon Road, London, E. C. 1, England, have invented certain new and useful. linproven'ients in Methods and Apparatus for Applying Printing Sheets to Their Cylinders, of which the following is a specification.

This invention relates to apparatus for applying printing sheets to their cylinders.

Printing cylinders are usually formed with a gap, and it is only to the application of sheets to such kind of cylinders that the present invention refers.

An object of the present invention is to provide a method and means for bending a sheet and forming it with turned over-ends spaced apart so that the distance between the folds is equal to the circumference of the cylinder to which the sheet is to be applied, less the width of the gap, whereby a sheet is prepared for immediate application to a printing cylinder.

A. further object is to obtain a means of forming a sheet so that its turned over ends are reinforced, and so that the turned over ends are of correct length from the respective folds, havingin mind the depth of the cylinder gap.

Another object is to devise a simple method and apparatus for bending and forming a sheet with turned over ends in one continuous operation.

Another object is to obtain an apparatus in the nature of a former, of which the edective surface is variable so that the former can be used for the preparation of sheets for cylinders of various diameters.

A still further object is to obtain a former which is rotatable for bending and forming a sheet with turned over ends in one revolution.

Another object is to construct a segmental former of which the convex surface isquickly and easily variable in length.

In the accompanying drawings is illustrated a preferred construction of apparatus for carrying into effect the present invention. tion.

In the drawings:

Figures 1 and 2 are side elevations showing respectively the beginning and end of a wrapping operation; and Fig. 3 illustrates pictorially a sheet provided with reinforced ends for use with a former as illustrated in 1 and 2.

Referring to the drawings, the reference 1 indicates a drum of a tensioning device, which drum is supposed to be one that can only be turned by the application of consid erable force against the action of brakes applied to resist rotation, for instance, a drum as described in joint U. S. Patent No. 1,478,947.

The chain or cable 2 is attached to the pe riphery of the drum 1, and also to the clamping device 3 in which one end of the, sheet is held.

As shown by Fig. 3, both ends 1 and 5 of the sheet are stiffened by rods or wlres rolled therein, the sheet adjacent thereto be ing provided with the two series of slots 6 and 7 respectively.

The segmental former is of substantially semicircular shape, and comprises a convex face 8 which terminates in sharp edges 9 and 10 corresponding to the longitudinal edge of a printing cylinder gap, the edges 9 and 10 being formed by providing flat faces 11 and 12 contiguous to the convex face at each end thereof. The convex surface 8 between the edges 9 and 10 has a length equal to the circumference of the printing cylinder to which a sheet being shaped on the former is to be applied, less the width of the cylider gap.

The edges formed at 9 and 10 may be formed to correspond to the longitudinal edges of the cylinder gap by setting the flat faces 11 and 12 at an angle to the convex face 8 equal to the angle between the circumference of the printing cylinder and the walls of its gap.

The face 11 is provided with studs or projections 13, over which the slots 7 of the sheet will engage as illustrated in Fig. 1, when the corresponding wall of the cylinder gap has such projections and a sheet with slots at the leading end is being used.

The end of the convex surface comprising the edge 10 is preferably included in an interchangeable portion 14L which is easily removable from the body of the former and comprises a continuation of the convex face on the former body and the flat face 12 contiguous to the continuation surface, at the junction of which the edge 10 is formed. By arranging the portion 14 as an interchangeable member, the eflective length of the convex surface of the former may be varied by substituting a portion having a different length of continuation surface, so that the said former may be used in the preparation of sheets for cylinders of various diameters.

A segmental former according to the present invention is preferably hollow, as indicated in the drawings, and provided with webs, such as 15, extending alorg its sides. The webs 15 may each carry ren'iovablc bearings, as indicated at 16, by which the former is mounted on its axle, indicated at 17.

In the arrangement shown, the line of strain is tangential to the surface on which the sheet is being wrapped, in accordance with the method of applying sheets to cylinders described and claimed in joint U. S. Patent No. 1,458,471.

In operation, one end of the sheet, for in stance, the end with the slots 7, may be placed over the studs 13 on the former, the other end of the sheet being engaged in the clamp 3 of the tensioning device, the brake of which will then be applied so that the sheet is stressed mechanically while the semicircular former is held aganst rotation. The former will then be rotated in an anticlockwise direction through 860 against the strain of tho tensioning device.

During the first half of the rotation the. sheet will be first folded over the corner 9, when one turned over end will be formed to lit on the corresponding face of the cylinder gap to which the sheet is to be applied. The sheet is then progressively wrapped around half of the convex face (tension being maintained), and during the continued rotation of the former through the latter half of one revolution, will be wrapped around the other half of the convex surface and the free end bent over the edge 10, thereby forming the second fold and providing the other turned over end.

As the convex surface between the edges 9 and 10 is of predetermined length, the sheet will have been bent and formed with turned over ends (in a continuous operation under tension), the folds being at precisely the correct distance apart to suit the printing cylinder to which it is to be applied.

If the sheet is not of the required length to lit the cylinder, having in mind the depth of the gap of the cylinder, it is necessary to perform an initial operation before using the former and tensioning device before described, this initial operation consisting in cutting off the sheet to precisely the right length, and this may be efiected by laying flat a sheet little longer than necessary and disposing rods or similar reinforcing members towards each end at a distance apart equal to the required length of the sheet. The ends of the sheet are then folded over the rods while their spacing is maintained, and a reinforced sheet of required length is then obtained.

A sheet so constructed ant applied to a former in the manner above referred to will be so formed that the reinforcing rods lit under the studs or projections in the gap the cylinder, while the folds in the sheet cancer by passing it over the edges 5) and it) of the former correspond ere lly with the edges formed between the cylindrica face and the alls of the gap of the printing cylinder.

arrangement of the former bearin.

rhe is preferably such that when a complete rolland bending operation has been effected, the line of strain includes the edges and contiguous face 12 of the former, 1. e., the edge and face farthest from the tensionin r device.

I claim:

1. Method of preparing a printin sheet for innnediate application to a printing cylinder having a gap consisting in forming the sheet of correct length, and stressing the sheet, and while the stress is n'iaintained. bc1ling the sheet over sharp edges spaced apart by convex segmental surface of a length equal to the circun'iference of the printing cylinder less the width of the gap, whereby as a continuous operation first one end of the sheet is folded over. then the sheet bent. and finally the other end of the sheet folded over, the spacing and forming of the fold being such that it will coincide exactly with the longitudinal edges of the cylinder gap when a sheet has been applied to the cylinder.

2. A rotatable segmental former for preparing a printing sheet for immediate application to a printing cylinder having a gap, having a convex surface of a length equal to the circumference of the printing cylinder to which the sheet is to be applied, less the width of the gap, an edge at each end of the convex surface corresponding to the lon ritw dinal edges of the cylinder gap. and means for varying the length of the said surface.

3. A rotatable segmental former for preparing a printing sheet for immediate application to a printing cylinder having a gap, comprising a convex surface, an interchangeable end portion. including a continuation of the convex surface and an edge at the end of the continuation. and an edge at the other end of said surface, the said edges corresponding to the longitudinal edges of the cylinder gap, and the convex surface plus the continuation surface having a length equal to the circumference of the printing cylinder to which the sheet is to be applied, less the width of the gap.

t. A. rotatable segmental former for preparing a printing sheet for immediate application to a printing cylinder having a gap,

comprising a convex surface, an interchangeable end portion, including a continuation of the convex surface and an edge at the end of the continuation, a flat surface contiguous to the convex surface at the other end forming an edge therewith, said edges corresponding to the longitudinal edges of the cylinder gap, and projections on the flat surface for anchoring the leading end of the sheet, the convex surface plus the continuation surface having a length equal to the circumference of the printing cylinder to which the sheet is to he applied, less the width of the gap.

5. A rotatable segmental former for pre paring a printing sheet for immediate application to a printing cylinder having a gap, comprising a convex surface. an interchangeable end portion including a continuation of the convex surface and a flat surface contiguous to the continuation surface, forming an edge therewith, and a fiat surface con tiguous with the convex surface at the other end forming an edge therewith. the flat surfaces each including between them and the continuation of the convex surface and the convex surface respectively an angle approximately equal to the angle between the cylindrical face and the walls of the cylinder gap, the convex surface plus the continuation surface having a length equal to the circumference of the printing cylinder to which the sheet is to be applied, less the width of the gap.

A hollow rotatable segmental former for preparing a printing sheet for immediate application to a printing cylinder having a gap, having a convex surface of a length equal to the circumference of the printing cylinder to which the sheet is to be applied, less the width of the gap, an edge at each end of the convex surface corresponding to the longitudinal edges of the cylinder gap, means for varying the length of the said surface, a web along each side of the convex. surface, and a bearing in each web for an axle for the said former.

7. A rotatable former of substantially sen1i-circular shape, for bending sheets for a printing cylinder having a gap, and having the convex surface as long as the circumference of the printing cylinder to which the sheet is to be applied, less the width of the gap, an edge at each end of the convex surface corresponding to the longitudinal edges of the printing cylinder gap, and means for varying the length of the said surface.

In testimony whereof I affix my signature.

MALCOLM OWEN. 

